This research seeks to characterize the process of symptom perception in pediatric asthma. This competing continuation application builds on the methodologic sophistication, multidisciplinary collaboration, and important basic findings established during the first period of support. The proposed research will pursue an assessment of the mechanisms, determinants, and moderating variables involved in the perception of respiratory changes. A three-component research plan is proposed. Component 1 will strengthen our understanding of the psychologic and physiologic correlates of perceptual ability. A positive association is expected between perceptual accuracy and a intelligence; b) attention; c) symptom focus; d) systemic steroid use; and e) predominantly large airway or mixed airway involvement. Component 2 will explore the relationship between chemosensitivity and resistive-load perception in high risk pediatric asthma patients. it is hypothesize that, compared to other asthmatics and controls, adolescents who have had near fatal asthma attacks will a) have higher thresholds for detecting resistive loads; b) will have a decreased response to progressive isocapneic hypoxia; and c) have a smaller increase in respiratory drive during progressive hypercapnia. Component 3 will characterize the family and self-management patterns s moderating variables between perception and morbidity. It is hypothesized that a) symptom perception will interact with family asthma management in relation to asthma morbidity b) poor symptom perception will be associated with worse medication compliance; and c) better family functioning will be related to better perception and lower functional morbidity. Methodologic approaches include a naturalistic clinical accuracy protocol; laboratory studies using a computerized resistive-loading apparatus to determine perceptual thresholds; a chemosensitivity protocol investigating drive; family assessment interviews, and computerized metered dose inhaler technology to assess compliance with asthma medications. The findings from this research are expected to ultimately provide the basis for an intervention to enhance perceptual accuracy in relevant subgroups of pediatric asthma patients. The research findings will also be of immediate use to physicians who must make judgments about the clinical stage of asthmatic patients and the best long-term approach to management.